﻿using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace CP.Utility
{
    public class EncryptHelper
    {
        public static string MD5(string input)
        {
            byte[] data = Encoding.Default.GetBytes(input);
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] result = md5.ComputeHash(data);
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < result.Length; i++)
            {
                sb.Append(result[i].ToString("x2"));
            }
            return sb.ToString();
        }

        //默认密钥向量
        private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

        /// <summary>
        /// DES加密字符串
        /// </summary>
        /// <param name="encryptString">待加密的字符串</param>
        /// <param name="encryptKey">加密密钥,要求为8位</param>
        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
        public static string EncryptDES(string encryptString, string encryptKey)
        {
            byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0,8));
            byte[] rgbIV = Keys;
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
            DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Convert.ToBase64String(mStream.ToArray());
        }

        /// <summary>
        /// DES解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
        public static string DecryptDES(string decryptString, string decryptKey)
        {
            byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
            byte[] rgbIV = Keys;
            byte[] inputByteArray = Convert.FromBase64String(decryptString);
            DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Encoding.UTF8.GetString(mStream.ToArray());
        }

        /// <summary>
        /// DES加密方法
        /// </summary>
        /// <param name="strPlain">明文</param>
        /// <param name="strDESKey">密钥</param>
        /// <param name="strDESIV">向量</param>
        /// <returns>密文</returns>
        public static string DESEncrypt(string strPlain, string strDESKey, string strDESIV)
        {
            //把密钥转换成字节数组
            byte[] bytesDESKey = ASCIIEncoding.ASCII.GetBytes(strDESKey);
            //把向量转换成字节数组
            byte[] bytesDESIV = ASCIIEncoding.ASCII.GetBytes(strDESIV);
            //声明1个新的DES对象
            DESCryptoServiceProvider desEncrypt = new DESCryptoServiceProvider();
            //开辟一块内存流
            MemoryStream msEncrypt = new MemoryStream();
            //把内存流对象包装成加密流对象
            CryptoStream csEncrypt = new CryptoStream(msEncrypt, desEncrypt.CreateEncryptor(bytesDESKey, bytesDESIV), CryptoStreamMode.Write);
            //把加密流对象包装成写入流对象
            StreamWriter swEncrypt = new StreamWriter(csEncrypt);
            //写入流对象写入明文
            swEncrypt.WriteLine(strPlain);
            //写入流关闭
            swEncrypt.Close();
            //加密流关闭
            csEncrypt.Close();
            //把内存流转换成字节数组，内存流现在已经是密文了
            byte[] bytesCipher = msEncrypt.ToArray();
            //内存流关闭
            msEncrypt.Close();
            //把密文字节数组转换为字符串，并返回
            return UnicodeEncoding.Unicode.GetString(bytesCipher);
        }




        /// <summary>
        /// DES解密方法
        /// </summary>
        /// <param name="strCipher">密文</param>
        /// <param name="strDESKey">密钥</param>
        /// <param name="strDESIV">向量</param>
        /// <returns>明文</returns>
        public static string DESDecrypt(string strCipher, string strDESKey, string strDESIV)
        {
            //把密钥转换成字节数组
            byte[] bytesDESKey = ASCIIEncoding.ASCII.GetBytes(strDESKey);
            //把向量转换成字节数组
            byte[] bytesDESIV = ASCIIEncoding.ASCII.GetBytes(strDESIV);
            //把密文转换成字节数组
            byte[] bytesCipher = UnicodeEncoding.Unicode.GetBytes(strCipher);
            //声明1个新的DES对象
            DESCryptoServiceProvider desDecrypt = new DESCryptoServiceProvider();
            //开辟一块内存流，并存放密文字节数组
            MemoryStream msDecrypt = new MemoryStream(bytesCipher);
            //把内存流对象包装成解密流对象
            CryptoStream csDecrypt = new CryptoStream(msDecrypt, desDecrypt.CreateDecryptor(bytesDESKey, bytesDESIV), CryptoStreamMode.Read);
            //把解密流对象包装成读出流对象
            StreamReader srDecrypt = new StreamReader(csDecrypt);
            //明文=读出流的读出内容
            string strPlainText = srDecrypt.ReadLine();
            //读出流关闭
            srDecrypt.Close();
            //解密流关闭
            csDecrypt.Close();
            //内存流关闭
            msDecrypt.Close();
            //返回明文
            return strPlainText;
        }
    }
}
